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2019-12-21PM / QoS: Redefine FREQ_QOS_MAX_DEFAULT_VALUE to S32_MAXLeonard Crestez1-1/+1
commit c6a3aea93571a5393602256d8f74772bd64c8225 upstream. QOS requests for DEFAULT_VALUE are supposed to be ignored but this is not the case for FREQ_QOS_MAX. Adding one request for MAX_DEFAULT_VALUE and one for a real value will cause freq_qos_read_value to unexpectedly return MAX_DEFAULT_VALUE (-1). This happens because freq_qos max value is aggregated with PM_QOS_MIN but FREQ_QOS_MAX_DEFAULT_VALUE is (-1) so it's smaller than other values. Fix this by redefining FREQ_QOS_MAX_DEFAULT_VALUE to S32_MAX. Looking at current users for freq_qos it seems that none of them create requests for FREQ_QOS_MAX_DEFAULT_VALUE. Fixes: 77751a466ebd ("PM: QoS: Introduce frequency QoS") Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Reported-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-21mmc: core: Re-work HW reset for SDIO cardsUlf Hansson1-0/+1
commit 2ac55d5e5ec9ad0a07e194f0eaca865fe5aa3c40 upstream. It have turned out that it's not a good idea to unconditionally do a power cycle and then to re-initialize the SDIO card, as currently done through mmc_hw_reset() -> mmc_sdio_hw_reset(). This because there may be multiple SDIO func drivers probed, who also shares the same SDIO card. To address these scenarios, one may be tempted to use a notification mechanism, as to allow the core to inform each of the probed func drivers, about an ongoing HW reset. However, supporting such an operation from the func driver point of view, may not be entirely trivial. Therefore, let's use a more simplistic approach to solve the problem, by instead forcing the card to be removed and re-detected, via scheduling a rescan-work. In this way, we can rely on existing infrastructure, as the func driver's ->remove() and ->probe() callbacks, becomes invoked to deal with the cleanup and the re-initialization. This solution may be considered as rather heavy, especially if a func driver doesn't share its card with other func drivers. To address this, let's keep the current immediate HW reset option as well, but run it only when there is one func driver probed for the card. Finally, to allow the caller of mmc_hw_reset(), to understand if the reset is being asynchronously managed from a scheduled work, it returns 1 (propagated from mmc_sdio_hw_reset()). If the HW reset is executed successfully and synchronously it returns 0, which maintains the existing behaviour. Reviewed-by: Douglas Anderson <dianders@chromium.org> Tested-by: Douglas Anderson <dianders@chromium.org> Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-18net: Fixed updating of ethertype in skb_mpls_push()Martin Varghese1-1/+1
[ Upstream commit d04ac224b1688f005a84f764cfe29844f8e9da08 ] The skb_mpls_push was not updating ethertype of an ethernet packet if the packet was originally received from a non ARPHRD_ETHER device. In the below OVS data path flow, since the device corresponding to port 7 is an l3 device (ARPHRD_NONE) the skb_mpls_push function does not update the ethertype of the packet even though the previous push_eth action had added an ethernet header to the packet. recirc_id(0),in_port(7),eth_type(0x0800),ipv4(tos=0/0xfc,ttl=64,frag=no), actions:push_eth(src=00:00:00:00:00:00,dst=00:00:00:00:00:00), push_mpls(label=13,tc=0,ttl=64,bos=1,eth_type=0x8847),4 Fixes: 8822e270d697 ("net: core: move push MPLS functionality from OvS to core helper") Signed-off-by: Martin Varghese <martin.varghese@nokia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-18Fixed updating of ethertype in function skb_mpls_popMartin Varghese1-1/+2
[ Upstream commit 040b5cfbcefa263ccf2c118c4938308606bb7ed8 ] The skb_mpls_pop was not updating ethertype of an ethernet packet if the packet was originally received from a non ARPHRD_ETHER device. In the below OVS data path flow, since the device corresponding to port 7 is an l3 device (ARPHRD_NONE) the skb_mpls_pop function does not update the ethertype of the packet even though the previous push_eth action had added an ethernet header to the packet. recirc_id(0),in_port(7),eth_type(0x8847), mpls(label=12/0xfffff,tc=0/0,ttl=0/0x0,bos=1/1), actions:push_eth(src=00:00:00:00:00:00,dst=00:00:00:00:00:00), pop_mpls(eth_type=0x800),4 Fixes: ed246cee09b9 ("net: core: move pop MPLS functionality from OvS to core helper") Signed-off-by: Martin Varghese <martin.varghese@nokia.com> Acked-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-18tcp: fix rejected syncookies due to stale timestampsGuillaume Nault1-0/+13
[ Upstream commit 04d26e7b159a396372646a480f4caa166d1b6720 ] If no synflood happens for a long enough period of time, then the synflood timestamp isn't refreshed and jiffies can advance so much that time_after32() can't accurately compare them any more. Therefore, we can end up in a situation where time_after32(now, last_overflow + HZ) returns false, just because these two values are too far apart. In that case, the synflood timestamp isn't updated as it should be, which can trick tcp_synq_no_recent_overflow() into rejecting valid syncookies. For example, let's consider the following scenario on a system with HZ=1000: * The synflood timestamp is 0, either because that's the timestamp of the last synflood or, more commonly, because we're working with a freshly created socket. * We receive a new SYN, which triggers synflood protection. Let's say that this happens when jiffies == 2147484649 (that is, 'synflood timestamp' + HZ + 2^31 + 1). * Then tcp_synq_overflow() doesn't update the synflood timestamp, because time_after32(2147484649, 1000) returns false. With: - 2147484649: the value of jiffies, aka. 'now'. - 1000: the value of 'last_overflow' + HZ. * A bit later, we receive the ACK completing the 3WHS. But cookie_v[46]_check() rejects it because tcp_synq_no_recent_overflow() says that we're not under synflood. That's because time_after32(2147484649, 120000) returns false. With: - 2147484649: the value of jiffies, aka. 'now'. - 120000: the value of 'last_overflow' + TCP_SYNCOOKIE_VALID. Of course, in reality jiffies would have increased a bit, but this condition will last for the next 119 seconds, which is far enough to accommodate for jiffie's growth. Fix this by updating the overflow timestamp whenever jiffies isn't within the [last_overflow, last_overflow + HZ] range. That shouldn't have any performance impact since the update still happens at most once per second. Now we're guaranteed to have fresh timestamps while under synflood, so tcp_synq_no_recent_overflow() can safely use it with time_after32() in such situations. Stale timestamps can still make tcp_synq_no_recent_overflow() return the wrong verdict when not under synflood. This will be handled in the next patch. For 64 bits architectures, the problem was introduced with the conversion of ->tw_ts_recent_stamp to 32 bits integer by commit cca9bab1b72c ("tcp: use monotonic timestamps for PAWS"). The problem has always been there on 32 bits architectures. Fixes: cca9bab1b72c ("tcp: use monotonic timestamps for PAWS") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-18inet: protect against too small mtu values.Eric Dumazet1-0/+5
[ Upstream commit 501a90c945103e8627406763dac418f20f3837b2 ] syzbot was once again able to crash a host by setting a very small mtu on loopback device. Let's make inetdev_valid_mtu() available in include/net/ip.h, and use it in ip_setup_cork(), so that we protect both ip_append_page() and __ip_append_data() Also add a READ_ONCE() when the device mtu is read. Pairs this lockless read with one WRITE_ONCE() in __dev_set_mtu(), even if other code paths might write over this field. Add a big comment in include/linux/netdevice.h about dev->mtu needing READ_ONCE()/WRITE_ONCE() annotations. Hopefully we will add the missing ones in followup patches. [1] refcount_t: saturated; leaking memory. WARNING: CPU: 0 PID: 9464 at lib/refcount.c:22 refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 9464 Comm: syz-executor850 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x3e kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:174 [inline] fixup_bug arch/x86/kernel/traps.c:169 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Code: 06 31 ff 89 de e8 c8 f5 e6 fd 84 db 0f 85 6f ff ff ff e8 7b f4 e6 fd 48 c7 c7 e0 71 4f 88 c6 05 56 a6 a4 06 01 e8 c7 a8 b7 fd <0f> 0b e9 50 ff ff ff e8 5c f4 e6 fd 0f b6 1d 3d a6 a4 06 31 ff 89 RSP: 0018:ffff88809689f550 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815e4336 RDI: ffffed1012d13e9c RBP: ffff88809689f560 R08: ffff88809c50a3c0 R09: fffffbfff15d31b1 R10: fffffbfff15d31b0 R11: ffffffff8ae98d87 R12: 0000000000000001 R13: 0000000000040100 R14: ffff888099041104 R15: ffff888218d96e40 refcount_add include/linux/refcount.h:193 [inline] skb_set_owner_w+0x2b6/0x410 net/core/sock.c:1999 sock_wmalloc+0xf1/0x120 net/core/sock.c:2096 ip_append_page+0x7ef/0x1190 net/ipv4/ip_output.c:1383 udp_sendpage+0x1c7/0x480 net/ipv4/udp.c:1276 inet_sendpage+0xdb/0x150 net/ipv4/af_inet.c:821 kernel_sendpage+0x92/0xf0 net/socket.c:3794 sock_sendpage+0x8b/0xc0 net/socket.c:936 pipe_to_sendpage+0x2da/0x3c0 fs/splice.c:458 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x3ee/0x7c0 fs/splice.c:636 splice_from_pipe+0x108/0x170 fs/splice.c:671 generic_splice_sendpage+0x3c/0x50 fs/splice.c:842 do_splice_from fs/splice.c:861 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1035 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:990 do_splice_direct+0x1da/0x2a0 fs/splice.c:1078 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441409 Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffb64c4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 0000000000073b8a R08: 0000000000000010 R09: 0000000000000010 R10: 0000000000010001 R11: 0000000000000246 R12: 0000000000402180 R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds.. Fixes: 1470ddf7f8ce ("inet: Remove explicit write references to sk/inet in ip_append_data") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17mfd: rk808: Fix RK818 ID templateDaniel Schultz1-1/+1
commit 37ef8c2c15bdc1322b160e38986c187de2b877b2 upstream. The Rockchip PMIC driver can automatically detect connected component versions by reading the ID_MSB and ID_LSB registers. The probe function will always fail with RK818 PMICs because the ID_MSK is 0xFFF0 and the RK818 template ID is 0x8181. This patch changes this value to 0x8180. Fixes: 9d6105e19f61 ("mfd: rk808: Fix up the chip id get failed") Cc: stable@vger.kernel.org Cc: Elaine Zhang <zhangqing@rock-chips.com> Cc: Joseph Chen <chenjh@rock-chips.com> Signed-off-by: Daniel Schultz <d.schultz@phytec.de> Signed-off-by: Heiko Stuebner <heiko@sntech.de> Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17quota: Check that quota is not dirty before releaseDmitry Monakhov1-0/+10
commit df4bb5d128e2c44848aeb36b7ceceba3ac85080d upstream. There is a race window where quota was redirted once we drop dq_list_lock inside dqput(), but before we grab dquot->dq_lock inside dquot_release() TASK1 TASK2 (chowner) ->dqput() we_slept: spin_lock(&dq_list_lock) if (dquot_dirty(dquot)) { spin_unlock(&dq_list_lock); dquot->dq_sb->dq_op->write_dquot(dquot); goto we_slept if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) { spin_unlock(&dq_list_lock); dquot->dq_sb->dq_op->release_dquot(dquot); dqget() mark_dquot_dirty() dqput() goto we_slept; } So dquot dirty quota will be released by TASK1, but on next we_sleept loop we detect this and call ->write_dquot() for it. XFSTEST: https://github.com/dmonakhov/xfstests/commit/440a80d4cbb39e9234df4d7240aee1d551c36107 Link: https://lore.kernel.org/r/20191031103920.3919-2-dmonakhov@openvz.org CC: stable@vger.kernel.org Signed-off-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17compat_ioctl: add compat_ptr_ioctl()Arnd Bergmann1-0/+7
commit 2952db0fd51b0890f728df94ac563c21407f4f43 upstream. Many drivers have ioctl() handlers that are completely compatible between 32-bit and 64-bit architectures, except for the argument that is passed down from user space and may have to be passed through compat_ptr() in order to become a valid 64-bit pointer. Using ".compat_ptr = compat_ptr_ioctl" in file operations should let us simplify a lot of those drivers to avoid #ifdef checks, and convert additional drivers that don't have proper compat handling yet. On most architectures, the compat_ptr_ioctl() just passes all arguments to the corresponding ->ioctl handler. The exception is arch/s390, where compat_ptr() clears the top bit of a 32-bit pointer value, so user space pointers to the second 2GB alias the first 2GB, as is the case for native 32-bit s390 user space. The compat_ptr_ioctl() function must therefore be used only with ioctl functions that either ignore the argument or pass a pointer to a compatible data type. If any ioctl command handled by fops->unlocked_ioctl passes a plain integer instead of a pointer, or any of the passed data types is incompatible between 32-bit and 64-bit architectures, a proper handler is required instead of compat_ptr_ioctl. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-12-13rfkill: allocate static minorMarcel Holtmann1-0/+1
commit 8670b2b8b029a6650d133486be9d2ace146fd29a upstream. udev has a feature of creating /dev/<node> device-nodes if it finds a devnode:<node> modalias. This allows for auto-loading of modules that provide the node. This requires to use a statically allocated minor number for misc character devices. However, rfkill uses dynamic minor numbers and prevents auto-loading of the module. So allocate the next static misc minor number and use it for rfkill. Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Link: https://lore.kernel.org/r/20191024174042.19851-1-marcel@holtmann.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-13jbd2: Fix possible overflow in jbd2_log_space_left()Jan Kara1-2/+2
commit add3efdd78b8a0478ce423bb9d4df6bd95e8b335 upstream. When number of free space in the journal is very low, the arithmetic in jbd2_log_space_left() could underflow resulting in very high number of free blocks and thus triggering assertion failure in transaction commit code complaining there's not enough space in the journal: J_ASSERT(journal->j_free > 1); Properly check for the low number of free blocks. CC: stable@vger.kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20191105164437.32602-1-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-13kernfs: fix ino wrap-around detectionTejun Heo1-0/+1
commit e23f568aa63f64cd6b355094224cc9356c0f696b upstream. When the 32bit ino wraps around, kernfs increments the generation number to distinguish reused ino instances. The wrap-around detection tests whether the allocated ino is lower than what the cursor but the cursor is pointing to the next ino to allocate so the condition never triggers. Fix it by remembering the last ino and comparing against that. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Fixes: 4a3ef68acacf ("kernfs: implement i_generation") Cc: Namhyung Kim <namhyung@kernel.org> Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-04net: skmsg: fix TLS 1.3 crash with full sk_msgJakub Kicinski1-13/+13
[ Upstream commit 031097d9e079e40dce401031d1012e83d80eaf01 ] TLS 1.3 started using the entry at the end of the SG array for chaining-in the single byte content type entry. This mostly works: [ E E E E E E . . ] ^ ^ start end E < content type / [ E E E E E E C . ] ^ ^ start end (Where E denotes a populated SG entry; C denotes a chaining entry.) If the array is full, however, the end will point to the start: [ E E E E E E E E ] ^ start end And we end up overwriting the start: E < content type / [ C E E E E E E E ] ^ start end The sg array is supposed to be a circular buffer with start and end markers pointing anywhere. In case where start > end (i.e. the circular buffer has "wrapped") there is an extra entry reserved at the end to chain the two halves together. [ E E E E E E . . l ] (Where l is the reserved entry for "looping" back to front. As suggested by John, let's reserve another entry for chaining SG entries after the main circular buffer. Note that this entry has to be pointed to by the end entry so its position is not fixed. Examples of full messages: [ E E E E E E E E . l ] ^ ^ start end <---------------. [ E E . E E E E E E l ] ^ ^ end start Now the end will always point to an unused entry, so TLS 1.3 can always use it. Fixes: 130b392c6cd6 ("net: tls: Add tls 1.3 support") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29futex: Add mutex around futex exitThomas Gleixner2-0/+2
commit 3f186d974826847a07bc7964d79ec4eded475ad9 upstream. The mutex will be used in subsequent changes to replace the busy looping of a waiter when the futex owner is currently executing the exit cleanup to prevent a potential live lock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.845798895@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29futex: Mark the begin of futex exit explicitlyThomas Gleixner1-28/+3
commit 18f694385c4fd77a09851fd301236746ca83f3cb upstream. Instead of relying on PF_EXITING use an explicit state for the futex exit and set it in the futex exit function. This moves the smp barrier and the lock/unlock serialization into the futex code. As with the DEAD state this is restricted to the exit path as exec continues to use the same task struct. This allows to simplify that logic in a next step. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.539409004@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29futex: Split futex_mm_release() for exit/execThomas Gleixner1-2/+4
commit 150d71584b12809144b8145b817e83b81158ae5f upstream. To allow separate handling of the futex exit state in the futex exit code for exit and exec, split futex_mm_release() into two functions and invoke them from the corresponding exit/exec_mm_release() callsites. Preparatory only, no functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.332094221@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29exit/exec: Seperate mm_release()Thomas Gleixner1-2/+4
commit 4610ba7ad877fafc0a25a30c6c82015304120426 upstream. mm_release() contains the futex exit handling. mm_release() is called from do_exit()->exit_mm() and from exec()->exec_mm(). In the exit_mm() case PF_EXITING and the futex state is updated. In the exec_mm() case these states are not touched. As the futex exit code needs further protections against exit races, this needs to be split into two functions. Preparatory only, no functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.240518241@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29futex: Replace PF_EXITPIDONE with a stateThomas Gleixner2-1/+34
commit 3d4775df0a89240f671861c6ab6e8d59af8e9e41 upstream. The futex exit handling relies on PF_ flags. That's suboptimal as it requires a smp_mb() and an ugly lock/unlock of the exiting tasks pi_lock in the middle of do_exit() to enforce the observability of PF_EXITING in the futex code. Add a futex_state member to task_struct and convert the PF_EXITPIDONE logic over to the new state. The PF_EXITING dependency will be cleaned up in a later step. This prepares for handling various futex exit issues later. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.149449274@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29futex: Move futex exit handling into futex codeThomas Gleixner2-15/+16
commit ba31c1a48538992316cc71ce94fa9cd3e7b427c0 upstream. The futex exit handling is #ifdeffed into mm_release() which is not pretty to begin with. But upcoming changes to address futex exit races need to add more functionality to this exit code. Split it out into a function, move it into futex code and make the various futex exit functions static. Preparatory only and no functional change. Folded build fix from Borislav. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.049705556@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds1-0/+6
Pull networking fixes from David Miller: 1) Validate tunnel options length in act_tunnel_key, from Xin Long. 2) Fix DMA sync bug in gve driver, from Adi Suresh. 3) TSO kills performance on some r8169 chips due to HW issues, disable by default in that case, from Corinna Vinschen. 4) Fix clock disable mismatch in fec driver, from Chubong Yuan. 5) Fix interrupt status bits define in hns3 driver, from Huazhong Tan. 6) Fix workqueue deadlocks in qeth driver, from Julian Wiedmann. 7) Don't napi_disable() twice in r8152 driver, from Hayes Wang. 8) Fix SKB extension memory leak, from Florian Westphal. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (54 commits) r8152: avoid to call napi_disable twice MAINTAINERS: Add myself as maintainer of virtio-vsock udp: drop skb extensions before marking skb stateless net: rtnetlink: prevent underflows in do_setvfinfo() can: m_can_platform: remove unnecessary m_can_class_resume() call can: m_can_platform: set net_device structure as driver data hv_netvsc: Fix send_table offset in case of a host bug hv_netvsc: Fix offset usage in netvsc_send_table() net-ipv6: IPV6_TRANSPARENT - check NET_RAW prior to NET_ADMIN sfc: Only cancel the PPS workqueue if it exists nfc: port100: handle command failure cleanly net-sysfs: fix netdev_queue_add_kobject() breakage r8152: Re-order napi_disable in rtl8152_close net: qca_spi: Move reset_count to struct qcaspi net: qca_spi: fix receive buffer size check net/ibmvnic: Ignore H_FUNCTION return from H_EOI to tolerate XIVE mode Revert "net/ibmvnic: Fix EOI when running in XIVE mode" net/mlxfw: Verify FSM error code translation doesn't exceed array size net/mlx5: Update the list of the PCI supported devices net/mlx5: Fix auto group size calculation ...
2019-11-22udp: drop skb extensions before marking skb statelessFlorian Westphal1-0/+6
Once udp stack has set the UDP_SKB_IS_STATELESS flag, later skb free assumes all skb head state has been dropped already. This will leak the extension memory in case the skb has extensions other than the ipsec secpath, e.g. bridge nf data. To fix this, set the UDP_SKB_IS_STATELESS flag only if we don't have extensions or if the extension space can be free'd. Fixes: 895b5c9f206eb7d25dc1360a ("netfilter: drop bridge nf reset from nf_reset") Cc: Paolo Abeni <pabeni@redhat.com> Reported-by: Byron Stanoszek <gandalf@winds.org> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-17Merge tag 'iommu-fixes-v5.4-rc7' of ↵Linus Torvalds1-2/+4
git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu Pull iommu fixes from Joerg Roedel: - Fix for Intel IOMMU to correct invalidation commands when in SVA mode. - Update MAINTAINERS entry for Intel IOMMU * tag 'iommu-fixes-v5.4-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: iommu/vt-d: Fix QI_DEV_IOTLB_PFSID and QI_DEV_EIOTLB_PFSID macros MAINTAINERS: Update for INTEL IOMMU (VT-d) entry
2019-11-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds1-0/+1
Pull networking fixes from David Miller: 1) Fix memory leak in xfrm_state code, from Steffen Klassert. 2) Fix races between devlink reload operations and device setup/cleanup, from Jiri Pirko. 3) Null deref in NFC code, from Stephan Gerhold. 4) Refcount fixes in SMC, from Ursula Braun. 5) Memory leak in slcan open error paths, from Jouni Hogander. 6) Fix ETS bandwidth validation in hns3, from Yonglong Liu. 7) Info leak on short USB request answers in ax88172a driver, from Oliver Neukum. 8) Release mem region properly in ep93xx_eth, from Chuhong Yuan. 9) PTP config timestamp flags validation, from Richard Cochran. 10) Dangling pointers after SKB data realloc in seg6, from Andrea Mayer. 11) Missing free_netdev() in gemini driver, from Chuhong Yuan. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (56 commits) ipmr: Fix skb headroom in ipmr_get_route(). net: hns3: cleanup of stray struct hns3_link_mode_mapping net/smc: fix fastopen for non-blocking connect() rds: ib: update WR sizes when bringing up connection net: gemini: add missed free_netdev net: dsa: tag_8021q: Fix dsa_8021q_restore_pvid for an absent pvid seg6: fix skb transport_header after decap_and_validate() seg6: fix srh pointer in get_srh() net: stmmac: Use the correct style for SPDX License Identifier octeontx2-af: Use the correct style for SPDX License Identifier ptp: Extend the test program to check the external time stamp flags. mlx5: Reject requests to enable time stamping on both edges. igb: Reject requests that fail to enable time stamping on both edges. dp83640: Reject requests to enable time stamping on both edges. mv88e6xxx: Reject requests to enable time stamping on both edges. ptp: Introduce strict checking of external time stamp options. renesas: reject unsupported external timestamp flags mlx5: reject unsupported external timestamp flags igb: reject unsupported external timestamp flags dp83640: reject unsupported external timestamp flags ...
2019-11-15mm/memory_hotplug: fix try_offline_node()David Hildenbrand1-0/+1
try_offline_node() is pretty much broken right now: - The node span is updated when onlining memory, not when adding it. We ignore memory that was mever onlined. Bad. - We touch possible garbage memmaps. The pfn_to_nid(pfn) can easily trigger a kernel panic. Bad for memory that is offline but also bad for subsection hotadd with ZONE_DEVICE, whereby the memmap of the first PFN of a section might contain garbage. - Sections belonging to mixed nodes are not properly considered. As memory blocks might belong to multiple nodes, we would have to walk all pageblocks (or at least subsections) within present sections. However, we don't have a way to identify whether a memmap that is not online was initialized (relevant for ZONE_DEVICE). This makes things more complicated. Luckily, we can piggy pack on the node span and the nid stored in memory blocks. Currently, the node span is grown when calling move_pfn_range_to_zone() - e.g., when onlining memory, and shrunk when removing memory, before calling try_offline_node(). Sysfs links are created via link_mem_sections(), e.g., during boot or when adding memory. If the node still spans memory or if any memory block belongs to the nid, we don't set the node offline. As memory blocks that span multiple nodes cannot get offlined, the nid stored in memory blocks is reliable enough (for such online memory blocks, the node still spans the memory). Introduce for_each_memory_block() to efficiently walk all memory blocks. Note: We will soon stop shrinking the ZONE_DEVICE zone and the node span when removing ZONE_DEVICE memory to fix similar issues (access of garbage memmaps) - until we have a reliable way to identify whether these memmaps were properly initialized. This implies later, that once a node had ZONE_DEVICE memory, we won't be able to set a node offline - which should be acceptable. Since commit f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") memory that is added is not assoziated with a zone/node (memmap not initialized). The introducing commit 60a5a19e7419 ("memory-hotplug: remove sysfs file of node") already missed that we could have multiple nodes for a section and that the zone/node span is updated when onlining pages, not when adding them. I tested this by hotplugging two DIMMs to a memory-less and cpu-less NUMA node. The node is properly onlined when adding the DIMMs. When removing the DIMMs, the node is properly offlined. Masayoshi Mizuma reported: : Without this patch, memory hotplug fails as panic: : : BUG: kernel NULL pointer dereference, address: 0000000000000000 : ... : Call Trace: : remove_memory_block_devices+0x81/0xc0 : try_remove_memory+0xb4/0x130 : __remove_memory+0xa/0x20 : acpi_memory_device_remove+0x84/0x100 : acpi_bus_trim+0x57/0x90 : acpi_bus_trim+0x2e/0x90 : acpi_device_hotplug+0x2b2/0x4d0 : acpi_hotplug_work_fn+0x1a/0x30 : process_one_work+0x171/0x380 : worker_thread+0x49/0x3f0 : kthread+0xf8/0x130 : ret_from_fork+0x35/0x40 [david@redhat.com: v3] Link: http://lkml.kernel.org/r/20191102120221.7553-1-david@redhat.com Link: http://lkml.kernel.org/r/20191028105458.28320-1-david@redhat.com Fixes: 60a5a19e7419 ("memory-hotplug: remove sysfs file of node") Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visiable after d0dc12e86b319 Signed-off-by: David Hildenbrand <david@redhat.com> Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Keith Busch <keith.busch@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Nayna Jain <nayna@linux.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-13can: af_can: export can_sock_destruct()Oleksij Rempel1-0/+1
In j1939 we need our own struct sock::sk_destruct callback. Export the generic af_can can_sock_destruct() that allows us to chain-call it. Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
2019-11-12Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-0/+1
Pull kvm fixes from Paolo Bonzini: "Fix unwinding of KVM_CREATE_VM failure, VT-d posted interrupts, DAX/ZONE_DEVICE, and module unload/reload" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: MMU: Do not treat ZONE_DEVICE pages as being reserved KVM: VMX: Introduce pi_is_pir_empty() helper KVM: VMX: Do not change PID.NDST when loading a blocked vCPU KVM: VMX: Consider PID.PIR to determine if vCPU has pending interrupts KVM: VMX: Fix comment to specify PID.ON instead of PIR.ON KVM: X86: Fix initialization of MSR lists KVM: fix placement of refcount initialization KVM: Fix NULL-ptr deref after kvm_create_vm fails
2019-11-12Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds2-23/+13
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 TSX Async Abort and iTLB Multihit mitigations from Thomas Gleixner: "The performance deterioration departement is not proud at all of presenting the seventh installment of speculation mitigations and hardware misfeature workarounds: 1) TSX Async Abort (TAA) - 'The Annoying Affair' TAA is a hardware vulnerability that allows unprivileged speculative access to data which is available in various CPU internal buffers by using asynchronous aborts within an Intel TSX transactional region. The mitigation depends on a microcode update providing a new MSR which allows to disable TSX in the CPU. CPUs which have no microcode update can be mitigated by disabling TSX in the BIOS if the BIOS provides a tunable. Newer CPUs will have a bit set which indicates that the CPU is not vulnerable, but the MSR to disable TSX will be available nevertheless as it is an architected MSR. That means the kernel provides the ability to disable TSX on the kernel command line, which is useful as TSX is a truly useful mechanism to accelerate side channel attacks of all sorts. 2) iITLB Multihit (NX) - 'No eXcuses' iTLB Multihit is an erratum where some Intel processors may incur a machine check error, possibly resulting in an unrecoverable CPU lockup, when an instruction fetch hits multiple entries in the instruction TLB. This can occur when the page size is changed along with either the physical address or cache type. A malicious guest running on a virtualized system can exploit this erratum to perform a denial of service attack. The workaround is that KVM marks huge pages in the extended page tables as not executable (NX). If the guest attempts to execute in such a page, the page is broken down into 4k pages which are marked executable. The workaround comes with a mechanism to recover these shattered huge pages over time. Both issues come with full documentation in the hardware vulnerabilities section of the Linux kernel user's and administrator's guide. Thanks to all patch authors and reviewers who had the extraordinary priviledge to be exposed to this nuisance. Special thanks to Borislav Petkov for polishing the final TAA patch set and to Paolo Bonzini for shepherding the KVM iTLB workarounds and providing also the backports to stable kernels for those!" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/speculation/taa: Fix printing of TAA_MSG_SMT on IBRS_ALL CPUs Documentation: Add ITLB_MULTIHIT documentation kvm: x86: mmu: Recovery of shattered NX large pages kvm: Add helper function for creating VM worker threads kvm: mmu: ITLB_MULTIHIT mitigation cpu/speculation: Uninline and export CPU mitigations helpers x86/cpu: Add Tremont to the cpu vulnerability whitelist x86/bugs: Add ITLB_MULTIHIT bug infrastructure x86/tsx: Add config options to set tsx=on|off|auto x86/speculation/taa: Add documentation for TSX Async Abort x86/tsx: Add "auto" option to the tsx= cmdline parameter kvm/x86: Export MDS_NO=0 to guests when TSX is enabled x86/speculation/taa: Add sysfs reporting for TSX Async Abort x86/speculation/taa: Add mitigation for TSX Async Abort x86/cpu: Add a "tsx=" cmdline option with TSX disabled by default x86/cpu: Add a helper function x86_read_arch_cap_msr() x86/msr: Add the IA32_TSX_CTRL MSR
2019-11-12KVM: MMU: Do not treat ZONE_DEVICE pages as being reservedSean Christopherson1-0/+1
Explicitly exempt ZONE_DEVICE pages from kvm_is_reserved_pfn() and instead manually handle ZONE_DEVICE on a case-by-case basis. For things like page refcounts, KVM needs to treat ZONE_DEVICE pages like normal pages, e.g. put pages grabbed via gup(). But for flows such as setting A/D bits or shifting refcounts for transparent huge pages, KVM needs to to avoid processing ZONE_DEVICE pages as the flows in question lack the underlying machinery for proper handling of ZONE_DEVICE pages. This fixes a hang reported by Adam Borowski[*] in dev_pagemap_cleanup() when running a KVM guest backed with /dev/dax memory, as KVM straight up doesn't put any references to ZONE_DEVICE pages acquired by gup(). Note, Dan Williams proposed an alternative solution of doing put_page() on ZONE_DEVICE pages immediately after gup() in order to simplify the auditing needed to ensure is_zone_device_page() is called if and only if the backing device is pinned (via gup()). But that approach would break kvm_vcpu_{un}map() as KVM requires the page to be pinned from map() 'til unmap() when accessing guest memory, unlike KVM's secondary MMU, which coordinates with mmu_notifier invalidations to avoid creating stale page references, i.e. doesn't rely on pages being pinned. [*] http://lkml.kernel.org/r/20190919115547.GA17963@angband.pl Reported-by: Adam Borowski <kilobyte@angband.pl> Analyzed-by: David Hildenbrand <david@redhat.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Cc: stable@vger.kernel.org Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-11iommu/vt-d: Fix QI_DEV_IOTLB_PFSID and QI_DEV_EIOTLB_PFSID macrosEric Auger1-2/+4
For both PASID-based-Device-TLB Invalidate Descriptor and Device-TLB Invalidate Descriptor, the Physical Function Source-ID value is split according to this layout: PFSID[3:0] is set at offset 12 and PFSID[15:4] is put at offset 52. Fix the part laid out at offset 52. Fixes: 0f725561e1684 ("iommu/vt-d: Add definitions for PFSID") Signed-off-by: Eric Auger <eric.auger@redhat.com> Acked-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Cc: stable@vger.kernel.org # v4.19+ Acked-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2019-11-10Merge tag 'armsoc-fixes' of ↵Linus Torvalds2-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc Pull ARM SoC fixes from Olof Johansson: "A set of fixes that have trickled in over the last couple of weeks: - MAINTAINER update for Cavium/Marvell ThunderX2 - stm32 tweaks to pinmux for Joystick/Camera, and RAM allocation for CAN interfaces - i.MX fixes for voltage regulator GPIO mappings, fixes voltage scaling issues - More i.MX fixes for various issues on i.MX eval boards: interrupt storm due to u-boot leaving pins in new states, fixing power button config, a couple of compatible-string corrections. - Powerdown and Suspend/Resume fixes for Allwinner A83-based tablets - A few documentation tweaks and a fix of a memory leak in the reset subsystem" * tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: MAINTAINERS: update Cavium ThunderX2 maintainers ARM: dts: stm32: change joystick pinctrl definition on stm32mp157c-ev1 ARM: dts: stm32: remove OV5640 pinctrl definition on stm32mp157c-ev1 ARM: dts: stm32: Fix CAN RAM mapping on stm32mp157c ARM: dts: stm32: relax qspi pins slew-rate for stm32mp157 arm64: dts: zii-ultra: fix ARM regulator GPIO handle ARM: sunxi: Fix CPU powerdown on A83T ARM: dts: sun8i-a83t-tbs-a711: Fix WiFi resume from suspend arm64: dts: imx8mn: fix compatible string for sdma arm64: dts: imx8mm: fix compatible string for sdma reset: fix reset_control_ops kerneldoc comment ARM: dts: imx6-logicpd: Re-enable SNVS power key soc: imx: gpc: fix initialiser format ARM: dts: imx6qdl-sabreauto: Fix storm of accelerometer interrupts arm64: dts: ls1028a: fix a compatible issue reset: fix reset_control_get_exclusive kerneldoc comment reset: fix reset_control_lookup kerneldoc comment reset: fix of_reset_control_get_count kerneldoc comment reset: fix of_reset_simple_xlate kerneldoc comment reset: Fix memory leak in reset_control_array_put()
2019-11-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds2-5/+8
Pull networking fixes from David Miller: 1) BPF sample build fixes from Björn Töpel 2) Fix powerpc bpf tail call implementation, from Eric Dumazet. 3) DCCP leaks jiffies on the wire, fix also from Eric Dumazet. 4) Fix crash in ebtables when using dnat target, from Florian Westphal. 5) Fix port disable handling whne removing bcm_sf2 driver, from Florian Fainelli. 6) Fix kTLS sk_msg trim on fallback to copy mode, from Jakub Kicinski. 7) Various KCSAN fixes all over the networking, from Eric Dumazet. 8) Memory leaks in mlx5 driver, from Alex Vesker. 9) SMC interface refcounting fix, from Ursula Braun. 10) TSO descriptor handling fixes in stmmac driver, from Jose Abreu. 11) Add a TX lock to synchonize the kTLS TX path properly with crypto operations. From Jakub Kicinski. 12) Sock refcount during shutdown fix in vsock/virtio code, from Stefano Garzarella. 13) Infinite loop in Intel ice driver, from Colin Ian King. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (108 commits) ixgbe: need_wakeup flag might not be set for Tx i40e: need_wakeup flag might not be set for Tx igb/igc: use ktime accessors for skb->tstamp i40e: Fix for ethtool -m issue on X722 NIC iavf: initialize ITRN registers with correct values ice: fix potential infinite loop because loop counter being too small qede: fix NULL pointer deref in __qede_remove() net: fix data-race in neigh_event_send() vsock/virtio: fix sock refcnt holding during the shutdown net: ethernet: octeon_mgmt: Account for second possible VLAN header mac80211: fix station inactive_time shortly after boot net/fq_impl: Switch to kvmalloc() for memory allocation mac80211: fix ieee80211_txq_setup_flows() failure path ipv4: Fix table id reference in fib_sync_down_addr ipv6: fixes rt6_probe() and fib6_nh->last_probe init net: hns: Fix the stray netpoll locks causing deadlock in NAPI path net: usb: qmi_wwan: add support for DW5821e with eSIM support CDC-NCM: handle incomplete transfer of MTU nfc: netlink: fix double device reference drop NFC: st21nfca: fix double free ...
2019-11-08Merge tag 'xarray-5.4' of git://git.infradead.org/users/willy/linux-daxLinus Torvalds2-19/+1
Pull XArray fixes from Matthew Wilcox: "These all fix various bugs, some of which people have tripped over and some of which have been caught by automatic tools" * tag 'xarray-5.4' of git://git.infradead.org/users/willy/linux-dax: idr: Fix idr_alloc_u32 on 32-bit systems idr: Fix integer overflow in idr_for_each_entry radix tree: Remove radix_tree_iter_find idr: Fix idr_get_next_ul race with idr_remove XArray: Fix xas_next() with a single entry at 0
2019-11-06mm: thp: handle page cache THP correctly in PageTransCompoundMapYang Shi3-7/+23
We have a usecase to use tmpfs as QEMU memory backend and we would like to take the advantage of THP as well. But, our test shows the EPT is not PMD mapped even though the underlying THP are PMD mapped on host. The number showed by /sys/kernel/debug/kvm/largepage is much less than the number of PMD mapped shmem pages as the below: 7f2778200000-7f2878200000 rw-s 00000000 00:14 262232 /dev/shm/qemu_back_mem.mem.Hz2hSf (deleted) Size: 4194304 kB [snip] AnonHugePages: 0 kB ShmemPmdMapped: 579584 kB [snip] Locked: 0 kB cat /sys/kernel/debug/kvm/largepages 12 And some benchmarks do worse than with anonymous THPs. By digging into the code we figured out that commit 127393fbe597 ("mm: thp: kvm: fix memory corruption in KVM with THP enabled") checks if there is a single PTE mapping on the page for anonymous THP when setting up EPT map. But the _mapcount < 0 check doesn't work for page cache THP since every subpage of page cache THP would get _mapcount inc'ed once it is PMD mapped, so PageTransCompoundMap() always returns false for page cache THP. This would prevent KVM from setting up PMD mapped EPT entry. So we need handle page cache THP correctly. However, when page cache THP's PMD gets split, kernel just remove the map instead of setting up PTE map like what anonymous THP does. Before KVM calls get_user_pages() the subpages may get PTE mapped even though it is still a THP since the page cache THP may be mapped by other processes at the mean time. Checking its _mapcount and whether the THP has